Fibrosis, generally defined as the production of excessive amounts of connective tissue, develops as a consequence of diverse underlying diseases. Chronic inflammation or tissue damage/remodeling are typical fibrosis inducing events. Specific disease examples include idiopathic pulmonary fibrosis (IPF), liver fibrosis associated with the later stages of alcoholic and nonalcoholic liver cirrhosis, kidney fibrosis, cardiac fibrosis, and keloid formation resulting from abnormal wound healing [Wynn, T. A. (2004) Nature Reviews Immunology. 4: 583-594; Friedman, S. L. (2013) Science Translation Medicine. 5(167):1-17]. Additionally, fibrosis is a key pathological feature associated with chronic autoimmune diseases, including rheumatoid arthritis, Crohn's disease, systemic lupus erythematosus, and scleroderma. Diseases representing a dire unmet medical need include idiopathic pulmonary fibrosis (IPF), scleroderma and nonalcoholic steatohepatitis (NASH) related liver fibrosis. The increased incidence of NASH related liver fibrosis is expected to directly parallel those of type 2 diabetes and obesity.
Scleroderma is a rare chronic autoimmune disease characterized by the replacement of normal tissue with dense, thick fibrous tissue. While the exact underlying cause of scleroderma is unknown, the disease generally involves immune cell mediated activation of dermal myofibroblasts leading to the deposition of excessive amounts of extracellular matrix proteins (e.g., type I collagen) that causes a thickening of the skin and in some cases the hardening and eventual failure of multiple organs. At present, there is no cure for scleroderma. Treatment is limited to attempts to manage symptoms and typically requires a combination of approaches. While scleroderma localized to the skin is typically not life threatening, systemic scleroderma affecting multiple internal organs can be a life-threatening disease.